Characterisation of microstructure evolution during creep of P91 steel using the electron backscatter diffraction technique

ABSTRACT

The present work deals with the microstructure evolution during creep of P91 steel. In particular, the changes of prior austenite grain (PAG) and low-angle grain boundary (LAGB) during creep were studied using the electron backscatter diffraction (EBSD). Firstly, a series of crept specimens of P91 steel were prepared at 893 K under a constant stress of 145 MPa. Then, the EBSD measurements of these specimens were carried out. Subsequently, the PAGs were reconstructed successfully with the measured EBSD data, and the resultant distribution of LAGBs was calculated. Consequently, the obtained results suggested that the size of PAGs has not changed significantly during the whole creep. For the distribution of LAGBs, however, the peak shifted obviously to high angles during creep. In addition, it demonstrated that the EBSD method offers an effective and quantitative tool to characterise the microstructure evolution during creep of P91 steel.

KEYWORDS:

• Creep
• P91 steel
• prior austenite grain
• low-angle grain boundary
• EBSD

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time as the data are being used as part of an ongoing study.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by the financial supports of the National Natural Science Foundation of China [Grant. Nos. 61901373 and 51371142].